Among diseases afflicting mammals, and particularly humans, are many which are due to hyperproliferation of epidermal cells. Among such diseases are skin diseases such as basal cell carcinoma, malignant melanoma, squamous cell carcinoma, actinic keratosis, Bowen's Disease, papilloma, seborrheic kera- tosis, toxic eczema, allergic eczema, atopic dermatitis, ichthyosis, and psoriasis.
The present invention provides methods and compositions for treating such hyperproliferative skin diseases.
The methods and compositions of the invention involve cytokinins. Cytokinins are plant hormones involved in promoting growth and cell division in explants of plant tissue in culture in standard media, which contain auxins (another class of plant hormones) as well as vitamins, mineral salts, and sugar.
Among cytokinins are those which are 6-(substituted amino)purines, including kinetin (6-(furfuryl)aminopurine), zeatin (6-(3-hydroxymethyl, 3-methylallyl)aminopurine, 6-(3,3-dimethylallyl)aminopurine, 6-(benzyl)aminopurine, 6-(phenyl)aminopurine, 6-(n-alkyl)aminopurine, wherein the alkyl group has 4, 5 or 6 carbon atoms, and 6-(cyclohexyl)methylaminopurine.
Cytokinins have been observed to have various effects on mammalian cells in culture. Orr and McSwain, Cancer 10, 617-624 (1957); Johnson et al., Exptl. Cell Res. 85, 47-56 (1974); Hecht et al., Proc. Natl. Acad. Sci. (USA) 71, 4670-4674 (1974); Mookerjee et al., J. Reticuloendoth. Soc. 25, 299-314 (1979); Gordon and Seglen, Arch. Biochem. Biophys. 217, 282-294 (1982); Vesely et al., Endocrinology 116, 1887-1892 (1985).